REFLECTOR: Static port calibration

[lawrence epstein]

Duh, I had a brain fart! Sorry. It is the most reliable way to set your Barometer (at a field without reporting).
> 
> The runway threshold check is always a good idea, but will not verify
> your static port in flight.
> 
> My altimeter before calibration of the static port, agreed perfectly at
> rest. It should as my system was certified but IFR flight. The issue is
> at cruise speed, is the pressure at the port the same as the pressure a
> few feet in front of the plane.
> 
> Also never ever omit step 2 of teh Low Pass Safety Rule!
> 
> Scott
> 
> Laurence Coen wrote:
> > Al,
> > Your altimeter and your transponder encoder are connected to the same
> > static port and will always agree no matter who far off the static
> > pressure is. Not only that but your ground speed and your TAS not the
> > IAS should agree. In general, the IAS will be less than the TAS which
> > would indicate that both your AS and altitude are both off in the same
> > direction indicating that your static port is in a low pressure area.
> > Low Pass Safety Rules:
> > 1. Always wear a cowboy hat.
> > 2. Holler "YEE-HAW" at mid field.
> > 3. Focus 100% of your attention on flying the plane.
> > 4. Have someone else look at the altimeter.
> > The problem here is that there isn't enough headroom in a Velocity to
> > wear a cowboy hat. I, therefore, would like to describe the method I
> > used to calibrate my static port. GPS altitude. Before folks get
> > excited and say that GPS altitude can be +- 100 feet remember "can be"
> > but rarely is. Every time I fly as part of my instrument check I do a
> > three way altitude check. At the hold short line for runway 18 at OJC
> > my altitude is exactly 1100 feet. I check my aneroid altimeter and GPS
> > altitude against this benchmark. I almost never see a difference of
> > more than 20 feet on either altitude. The aneroid and GPS also track
> > on cross country flights. When I notice a difference I check a local
> > ATIS or AWOS and reset my colesman to the local barometer and they
> > again sync up. A WAAS enabled GPS will typically show altitude to
> > within 3 meters with a clear sky view.
> > Try it, you'll like it.
> > Larry Coen
> > N136LC
> >
> > *From:* Al Gietzen <mailto:ALVentures at cox.net>
> > *Sent:* Wednesday, March 04, 2009 9:40 AM
> > *To:* reflector <mailto:reflector at tvbf.org>
> > *Subject:* REFLECTOR: Static port calibration
> >
> > Out playing in the sky yesterday, I decided to do checks on altitude
> > and speed readings. I had never done the ‘low pass over the runway’
> > test. 150 KIAS, est 80 ft over the runway, altimeter readout on the
> > GRT EFIS was maybe 100 ft too high. Hum-m-m.
> >
> > Went out and flew the orthogonal square about the same speed;
> > recording GPS ground speed and IAS in each direction, then took the
> > average of each. The speeds agreed within 1.2 knots.
> >
> > I’ve always found my altitudes consistent with where ATC says I am –
> > so I don’t think I need to change anything.
> >
> > Al
> >
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